Quote:
Originally Posted by sandusky
hi, bracket diameteris 30mm. when i measure length of tube it's 830mm appox distance between mirrors is 730mm , why would u call it 900 focal length. sorry if i sound stupid but i'm new to this game. thanks for your help. des.
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Hi and welcome Des. You're where I was about 8 months ago with an dodgy DSE 114 f5 Newt and not much else. I bought a 20mm GSO Wideview ($49) a 12 mm Plossl ($29) a 2 x Barlow ($39) a red led finder ($39) and been enjoying ever since. Sure it's not the flashest, best scope in the world but if the mirror is reasonable and you can start to find your way around the sky like I am then go for it. Aperture fever comes later as I have found out. I only paid $50 for the scope and it cost me about $150 for the eyepieces etc. Haven't regretted it yet. In fact just starting to really enjoy it.
The 730mm between mirrors needs to be added to the distance from the diag to your eyepiece lens, about 170mm more obviously, because the light path has to take right turn so you can see it through the focusser.
A 20mm GSO will give you a magnification of 46x which in a good wideview is a nice usable size (imho) for scanning. Add the 2 x Barlow and you effectively have a 10 mm at 92 mag which will give you a dimmer but acceptable close up of the object. They are the combination I use most of the time and if you ugrade your scope later they are still quite useable.
If you've got a pair of binoculars to scan the skies before you hunt for them on the scope it is an immense help. You'll be surpised at what you can see and it helsp you get familiar with the recognisable groups.
Enjoy and learn.